Needles in pen left inky top (5)
I believe the answer is:
styli
'needles' is the definition.
(I've seen this before)
'pen left inky top' is the wordplay.
'pen' becomes 'sty' (both can mean an animal enclosure).
'top' indicates taking the first letters.
The initial letters of 'left inky' is 'li'.
'sty'+'li'='STYLI'
'in' acts as a link.
(Other definitions for styli that I've seen before include "Writers of old" , "Gramophone needles" , "What engravers use" , "writing implements" , "Writing, engraving, tools" .)